Tin has put up on the Read or Die website the mechanics for the cosplay competition at the Manila International Book Fair. What I want to comment is how visual cosplay is, yet literary characters aren't as quickly as recognizable unless they were adapted to another medium such as TV or movies. For example, we presently have an image of what Conan (the Barbarian) or Harry Potter or Aragorn or Sherlock Holmes or Baron Harkonnen should look like (even the cast of Noli me Tangere will be identified by their period costumes more than their physical characteristics). Not so much for Belgarath the Sorcerer (will be mistaken for generic white-bearded sorcerer or another sorcerer from the series), Rand 'Al Thor (or Richard Rahl, or King Arthur, or generic fantasy hero with a sword), or Hari Seldon (is that a Starfleet uniform?). Of course I think there will be some notable exceptions. How many wizard/fighter albinos bearing Stormbringer do you know of? Polgara might be recognizable although that's more of a hair thing rather than a whole costume make-over (owl rejects from Harry Potter help too). Then there's characters that are the products of repetitive descriptions (is that a mark of good writing or bad writing?) like Raistlin and his hourglass eyes (good luck with the rest of the cast of Dragonlance... Goldmoon can be mistaken for Galadriel with a staff, Sturm your generic knight without helmet, Riverwind a cross between a native American barbarian, and Flint for Gimli). Then there's some characters that can be pulled off if done correctly. Phedre I think is doable (yay, bondage!). The cast of A Song of Ice and Fire is possible if the costume matches the coat of arms of each House (although I imagine handless Jamie can be mistaken for Luke Skywalker--look, I have no right hand!). Ender and his jeesh, difficult to pull off but possible (and will win the "awww, they're cute children" award).
Or some group could dress up as Old Ones and drive everyone mad. Except they'll probably say "isn't that the dude from Pirates of the Carribean?" (Don't get me started with mysteries--I keep thinking of Nighthood for Arsene Lupin [not Richard Guitterez!] and Detective Hercule Poirot will be confused as Dr. Evil with a mustache.)